/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/wait.h>

#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#include "conf.h"

#define CF_DEFSIZE      32      /* Starting table size */
#define CF_GROW         2       /* Table size multiplier on grow */

static FILE *
open_conf_pipe(const char *cmd, char *argv[], pid_t *pidp)
{
        int pfds[2];
        pid_t pid;
        struct sigaction act;

        /* Create a pipe and fork a child process to run the command */

        if (pipe(pfds) == -1) {
                logerror("failed to create pipe");
                return (NULL);
        }

        if ((pid = fork1()) == -1) {
                logerror("failed to fork1");
                goto err;
        }

        /* If we're in the child, run the command and output to the pipe */

        if (pid == 0) {
                /*
                 * We must set up to ignore these signals, which may be
                 * propogated from the calling process.
                 */

                act.sa_handler = SIG_IGN;

                (void) sigaction(SIGHUP, &act, NULL);
                (void) sigaction(SIGALRM, &act, NULL);
                (void) sigaction(SIGUSR1, &act, NULL);

                (void) close(pfds[0]);
                (void) close(STDOUT_FILENO);

                if (dup2(pfds[1], STDOUT_FILENO) == -1) {
                        logerror("failed to dup to stdout");
                        (void) close(pfds[1]);
                        _exit(127);
                }

                (void) execvp(cmd, argv);
                logerror("failed to parse configuration file");
                _exit(127);
                /*NOTREACHED*/
        }

        /* If we're in the parent, open the read end of the pipe and return */

        *pidp = pid;
        (void) close(pfds[1]);
        return (fdopen(pfds[0], "r"));

err:
        (void) close(pfds[0]);
        (void) close(pfds[1]);
        return (NULL);
}

static void
close_conf_pipe(FILE *fp, pid_t pid)
{
        int status;

        while (waitpid(pid, &status, 0) == -1) {
                if (errno != EINTR)
                        break;
        }

        (void) fclose(fp);
}

static int
grow_conf_file(conf_t *cf)
{
        int ndsize = cf->cf_dsize ? cf->cf_dsize * CF_GROW : CF_DEFSIZE;
        void *ndtab = realloc(cf->cf_dtab, sizeof (char *) * ndsize);

        register char *p;
        int odsize, lines, i;

        if (ndtab == NULL) {
                logerror("failed to allocate config file table");
                return (-1);
        }

        lines = ndsize - cf->cf_dsize;
        odsize = cf->cf_dsize;

        cf->cf_dtab = (char **)ndtab;
        cf->cf_dsize = ndsize;

        for (i = 0; i < lines; i++) {
                if ((p = (char *)malloc(BUFSIZ)) == NULL) {
                        logerror("failed to allocate config file buffer");
                        return (-1);
                }

                cf->cf_dtab[odsize + i] = p;
        }

        return (0);
}

int
conf_open(conf_t *cf, const char *cmd, char *argv[])
{
        char *line, *p;
        pid_t pid;
        FILE *fp;

        (void) memset(cf, 0, sizeof (conf_t));

        if ((fp = open_conf_pipe(cmd, argv, &pid)) == NULL)
                return (-1);

        for (;;) {
                /* If we need to grow the table, do so now */

                if (cf->cf_lines >= cf->cf_dsize) {
                        if (grow_conf_file(cf) == -1)
                                goto err;
                }

                line = cf->cf_dtab[cf->cf_lines];

                /* Read the next line, and break out if we're done */

                if (fgets(line, BUFSIZ, fp) == NULL)
                        break;

                /* Strip newline and bump line counter */

                if ((p = strchr(line, '\n')) != NULL)
                        *p = '\0';

                cf->cf_lines++;
        }

        close_conf_pipe(fp, pid);
        return (0);

err:
        close_conf_pipe(fp, pid);
        return (-1);
}

void
conf_rewind(conf_t *cf)
{
        cf->cf_ptr = 0;
}

char *
conf_read(conf_t *cf)
{
        if (cf->cf_ptr < cf->cf_lines)
                return (cf->cf_dtab[cf->cf_ptr++]);

        return (NULL);
}

void
conf_close(conf_t *cf)
{
        int i;

        if (cf->cf_dtab != NULL) {
                for (i = 0; i < cf->cf_dsize; i++)
                        free(cf->cf_dtab[i]);
                free(cf->cf_dtab);
        }
}